Electrical oscillatory system and apparatus



Aug. 6, 1946.

w. P. MUELLER E T AL ELECTRICAL OSCILLATORY SYSTEM AND APPARATUS 2 Sheets-Sheet 1 Filed 001;. 30, 1941 o A 2 MW Lil K f A a 0 4 M Z .9 m 2 w m p w J t w 4/ m 6 g 7 INVENTORS MUELLER KISER fi v WILLIAM F.

IgTHANIEL g= 6, 194%- w. P. MUELLER ET AL ELECTRICAL OSCILLATORY SYSTEM AND APPARATUS Filed 001;. 30, 1941 a/camv LEAK v INVENTORS WILLIAM F. MUELLER N QIHANIEL L. KISER 2 Sheets-Sheet 2 at high frequencies Patented Aug. 6, 1946 William P. Mueller and Nathanielh Kiser, Emporium, Pa, assignors to Hygrade Sylvania Corporation, Emporium Massachusetts Pa., a corporation of Application October so, 1941; seriallnaeiuoes This invention refers to the production. and utilization of electrical oscillationsl and ;in particular to the design and arrangement of the, cir-.

cuit elements constituting the oscillationwcircuits of the type incorporating tuned transmission lines. 1 1

For the generation of high frequencies, in particular. of ultra-high frequencies of the order of several hundred megacycles, simple and effective oscillation circuits can be obtained'by connecting the two wires forminga tuned transmission line on one end of the line to grid and plate of a triode or pentode. The other end ofthe transmission line may be either short circuited, constituting a quarter wave line; or they may be open, constituting a half wave line.

1 Quarter wave lines are usually preferable to half wave lines, because of their higher Qvalue for 'given diameters of the wires forming the transmission line, andbecause the overall len th of the circuit is smaller.

The actual length of the ,transmission has only part. of the oscillationcircuit, which maybe considered as made up .of a transmission line closed by the reactance of the tube leads and the capacity formed'by grid and plate of the tube used inv the circuit; It is usually shorter than a quarter, (or a half) wave length. as'the effective reactance of the'tube elements andr leads is usually capacitive and. smallerthan the unit length capacity of the transmission line When the value of the effective grid to plate capacitance of the tube comes nearer to the unit length capacity of the transmission line, the actual length of the attached "tuned line becomes very short, and better stability maybe obtained by an open ended line, i. e. a half wave line, whose actual length may, howevennot be much larger thana quarterwave length. I e

Frequency stability in these oscillation circuits depends to, a large extent on the ratio ofthe capacitive reactanceofiered by the tube leads and electrodes to theunit length capacity of the transmission line. Better stability, or stability for a given tube may, therefore, be obtained if two transmission lines are attached to opposite ends of the tube elements symmetrically. In the case of two quarter wave lines, the tube is placed into the center of a half wave line, closed at both ends by a short circuit, and in'order practically to divide the tube capacity into two halves, it is necessary to provide a tube'with'symmetrical leads atth'etwo ends of the grid and at the two ends of theanode. This known arrangement of double ended connection 5Claims. (o1. fascist) hasiseveral effects. Each of thectwotuned lines wo substan ially on y. i to. ha th ubefi e aotance,and the current through each of the tube leads,.,'is nnly labout half of the c'ur'rent flOWin'g through each'lead; in the caseofa single trans; rmssi'onjline circuit. f 1

4 A ,numberf of. different tube designs have been carried out which allow efiectiye operation in such. a double-ended ,'synnnetrical tuned line'circuit, A typical arrangement. is shown,in,a paper by A. L Samuel, I. R. E, Proceedingspages1243+ 1252, October 1937. The tubes ,used in these known arrangements are expensive and the problem presented by the symmetrical seals at oppor site ends of the plate electrode and of the 'grid electrode through lthe envelope requires the full attention 'of an experienced 8.1 5 lower, Other disadvantages of the knownjdouble-ended tuned line circuit are its doubled overalllength and the inconvenience in tuning. This. tuning is gene l 'r a r ed o t by va ying he. length of ea h transmission line by telescoping rods or tubings at the twoends far removed from the oscillator tube. It is, therefore, the main obJ'ectof'thisinyention to devise a double-endedultra-high frequenc oscillation circuit, .whi ch,fhas an overall length substantially equal to that'of, the single tuned transmissionline circuit 7 I Another main object of the invention. refers tothebonstmction and circuit application of a tube, which is provided with twosymmetrical end leads for theplate electrode and two symmetrical end leads for. the, grid electrode, and which can be sealed and manufacturedentirely with the standard equipment used for the production of ordinary radio receiving tubes. 1 Finally, it is a main objectof the invention, to build a double ended transmission line circuit, in which two', tuned lines can be 1 simultaneously tuned to anydesired frequency .within limits.

A feature of the invention refers tothe cone struction of a quadruple gang tuning device cohsisting of four, parallel metal rods or tubes, which can be telescoped into or over'four otherpieces of tubing which form the two branches of' two tunedlines. l

Another feature of the invention refers tothe' mutual or what may he termed folded over positionof thetwo tuned lines of a double-ended transmission line circuit. r V

A feature of the invention refers to the spacing of, the. different ,wires or tubings adapted to fit directly into'the, twof grid andthetwo plate lead pins of radio tube base headers. 3

, The invention will now be describedimconnece.

tion with-tli ejldjawing'sjiwhich show carried out for two symmetrical lines with certain modifications. f

For obvious reasons, the plate voltage is al t mi ma e] up with two'smnmetrical tuned"h'alf wave lines, it being understood that the invention may be quarter wav'e' plied to a. point of the transmission line in which the high frequency voltage is re, andltlie-high frequency current is a maximum; In {the case of a. half wave line, one high frequency voltage maximum is at the open end of the line, another at the tube itself. .Between these two" points,

and. a. voltage node, and the D. C. plate voltage lead is, therefore,- connected, to this. po int. I v In'the case-of the ,q'u'arte'r wa eline' whic'his short circuit'eda ein x qv dfi f he tu e, the. voltage] node s at the, short circuit'ed end- Inorde'r to block ,the, grid ofth riodefrom fthe; D. C. voltage, a D; Cfblockin'g b, enser,must be introduced. This blocking c"o' 'denser i'may be" placed at an convenie' tjpoint,butis preferably introduced at the 1 far endflof the quarter. wave line, where it may serve the purpose of 'a high frequency short circuit at thejsame time, The D. C. voltage leadis'themconnected to the plate side of the blocking condenser.

Fig. 1 shows aschematicdiagram of aconvena tional double-ended ,circuit for operation of a single'tube withtwo half wave lines Fig. 2 showsa sch t'c diagram itheinew double-ended circuit; .1

. Fig. 3 shows'a perspective viewj of fthe new.

double-ended circuit, including the mounting;

. Figs. 4 ends show. details of, a triodetube c onstruction adapted for operation infthe, new cir cuit. 1 l I Fig. 6 is a detail View of the tube and socket portions of .the system. 'Fig. .7 is afls ecti theline 1 -1 thereof; Y

' Fig. '8 is a schematic diagram to"explain certain features of theinvention. Y

Referring to Fig.5 1' Qwhich', represents sche- ,1

matically adouble-e'nded oscillator-jgeneratorcircuitthenumeral l represents,airelectron dis-. charge tube'with plate 2,, grid 3.and,cath de 4. The plate lead-inlconductors and ,6 are sealed through the wall'oftubeI atopposite ends of they plate electrode, and parallelft'o them are sealedin the gridleadsfl'l' and. Thedistances ,between 51am Landbetweenfi, 8, are equal to each other and toth distance between the parallel conductor tubings 5, and i0 and, of theficonduct'o'r tubingsll' and J2 respectively, these tubings being directly, connected to'the corresponding lead-in conductors.g

Tuning extensionafixed'iniIlSulating spacers:

l3 and 14 -are telescoped intothetwo farends of the transmission line. They, consist of pairs of metal rods l5, l6, H, l8, whichslide snugly inside the tubings 9. l0, and H, I.2 respectively. The D- Qconnection, toplate 2 from the positive D. C. highvolt'age terminal. [9, and from grid 3 to grid leak and to ground, andfrom the cathode 4. over choke coil z l to -ground, are indicated in I It will be noted, that the ultrafhigh irequency currents the w e-lat lsaii lil t at w multaneously either towardsthe plate, or simulnail view ofjEig. eit kn along a ,From the foregoing, it will be seen that in order to" tune the system, the members l3 and I4 must "-bei simultaneously moved in unison in opposite directions. Not only does this require precision adjustment apparatus for both ends of the system', but italso requires considerable space because. allowance must be made for the maximum outward movement of members l5-l 8. Furthermore, the sys tem requires a special constructed tube-wherein the lead-in pin or wires are spenearer to the tube end, is a current maximum '2 Plate 22 is providedatopposite'endsjwith symmetric leadin wires or.,pins. 24, 25 (it bein understood ,that thebulb' of thetube and the cathode are omitted 'for purposesof explanation) and likewise grid'23 is provided at opposite ends with lead-in wires'olr pins 26 21 The four, lead-in wires'are. connected directly to the tuning transmissionline eXtensi0nsZ8-3l, all of which are'of tubular conductive.materialjand extendv in the same direction from, the electrode as emb andra al s to s Ot e Ex en m are. Provi d w h s i 1 i hafs i nttedttelescqping metjal mang r, whichare rigidly united attheirremotefends by theinsu lation block 36. The system ofFigQZ can'th'cn be considered "as that of Fig. l if the "latter were 1d eiih f1fwd H- '1 "1 In the"foldedove rf" position, the two half wave lines 7 do not extend in opposite directions from thev tub T r mi iqwa f u i e y em. erm n nsat Q1 and i t e te able pentndji and on the tube side, nto .the four double end leads of grid and'plateof the oscillator'tubeat the other end. The principal advantage of the double-ended circuit of Fig.1}, viz'i ,'a n increase of the upper frequency limitjover that of a single half wave line; is however still obtained, while the main disadvantages ofthe double endedbpelfation ofFigJ are eliminated.

.. The overall length of the sy v stem is the'sameas forrsingle-ended transmission line operation. The

tuning-of the two lines canbe carried .out bya singleslidable vfour rod gang. attached to insulate ing. spacer .36, which may telescopically engage the stationary parts 28..-3l ofthe two lines connectedto the two ends of grid-andplate of the tube. Finally,-it is not necessaryto use a tube in which-individual seals through the-envelope are provided for obtaining two symmetrical leads fromeach of 'the tube electrodes to which' the quarter wave lines are'ponnectedr These expn sive; tubes may still be used, if desired, but the new circuit permitsth use of tubes in which Sim metrical double leads from the ends of each elec- "trode are carried through the single header at one end of the radio tube. 7 I

The actual working embodiment of the'invention shown in Fig. 3 consists of an L-shape'dmetal base 31, with a long horizontal part 38 and a short vertical leg 39. In the short leg is mounted a lock in tube base 40, carrying a lock-in tube 4l, with double-ended grid connections and double-ended plate'connections as-will'be 'de scribed in connection with Figs. 4-8'and as covered'in 'copend-in'g application Serial No. 416,440 Patent '#'2,301,914,' granted Nov. 17, 1942. The "four lead-pins'of grid and plate are arranged alternately in the corners of a' square.

Th tube is arranged to be plugged into a spring socket 42 of' any well-known construction; such for'example as the well-known "ctals0cket.

Preferably however, the socket is as shown inFigs.

f6 and] '7 consisting of an insulation button or wafer 43 into the periphery of which is molded a thin'm'etal mount ring 44 for attachmentto the plate 39. Button 43 has a series of eight openings therethrough arranged around the center thereof and in each of these openings is mounted a contact member. Into four of these openings are fastened the ends of the tubular metal members 28-3l which are held in place in the respective openings in button 43 in any suitable manner.

two heater pinswhich plug'in' to corresponding spring contacts mounted'i'n'thei-button'43. The ends ofthetubular members 28-31 which engage the pins on the plugged-in tube may be split or 1 otherwise radially expansible so as to grip resil- 'iently the corresponding tube pins 24-21. If the tube is of the'well-known lock in type, the base of the tube also has a central locating and looking member 45 which is adapted to contact with a metal sleeve 46 fastened in the button, one end of sleeve 46 being split or otherwise radially resilient and having an inwardly extending lip or fiange' 41 to engage the corresponding peripheral groove on the end of the locking member of the tube. The contact sleeve 46 is connected in any suitable way, for example by a short metal strap 48 to the grounded metal plate 39.

Instead of making the tuning extensions 28-3I an integral part of the socket, any conventional Octal socket can be employed with the members 283| soldered or otherwise fastened to the contact springs of the socket so as to form electrical elongations thereof. The members 283| in efiect therefore, form continuations of the respective tube pins and they are preferably of copper tubing, and extend parallel to each other at the distances fixed by the pin leads. At th end of these tubings 28-3l remote from the oscillator tube there are provided the four tuning rods 32-35 which are rigidly fixed parallel to each other in the insulating spacer block 36. The tuning rods which are rigidly mounted in insulating spacer 36 are spaced so as to be in axial alignment with the corresponding members 283l so that they snugly fit and telescope simultaneously into the said members. Spacer 36 also serves as a support of the transmission line array on the long leg 38 of the base plate, and provides a uniform spacing of the lines parallel to member 38. For

this purpose, member '33 is formed on its edge with two guiding lugs 50, 5|, which are slidable in parallel grooves 52, 53, in member 38.

Spacer 36 can be moved back and forth in the direction of the transmission lines, by means of a screw 54 and a threaded block 55 fastene'd'to member 38', whereby the tuning of the two transmission lines by equal amounts is simultaneously carried out.

By employing a tube such as shown in Figs. 4-6, as a part of the circuit the advantage is obtained that the two pairs of lead pins of the grid'and "plate electrodes are straight, direct continuations 'of theattached transmission lines, thus difiering ,as little as possible in unit length capacity and inductance from the transmission line constants.

' Due to the neighborhood of the'cathode and heater leads in the tube, the capacities of the plate and grid leads in the tube with respect to the cathode is, however, different from the ground capacities ofthe rods and tubings forming the transmission lines themselves, and it is necessary to balance cathode and heater with respect to ground. It has been found by experiment that this balancing may be carried out much easier by providing two cathode leads in the tube. The two cathode pins of tube 4| are connectedto the two ends of the cathode, similarly to the two pins connected to the two ends of the grid and the two :20"

pins connected to the two ends of the anode;

Fig. 8'shows schematically oneway of carrying out this balancing, parts of this figure corresponding to the parts of Figs. 2, 3, f1 and 5, bearing the same numerals. The opposite ends of the cathode 55 are connected to their respective pins'56, 51.

" Pin .56 is connected to ground through a series inductance 58 whil pin 51 is connectedthrough a series capacitor 59 to a proper point onthe leg 30 r of the transmission line connected to one end of the'grid' 23. -While Fig. 9 shows the 'four leg's'of the transmission line in the same plane, it will be understood of course that it is intended to represent the symmetrical arrangement of the legs as actually shown in Fig. 3. The positive-D.- C. potential supply is connected to the plate leg '29 of the tuned transmission line at the potential node point (5i). Likewise grid leak'6l is connected to potential node point 62 on leg30 and to member 38. With the proper potentials applied to the heater and with the proper bias applied to the cathode, all that is necessary to tune the circuit is to adjust the screw 54 whereby the eifective length of the transmission line is varied. If desired, additional metal removable side walls and top walls may be applied to the member 31 to constitute a closed box for the variable transmission line, it being understood that suitable insulated lead-in connections are provided. If desired, the L-shaped member 31 may be supplemented by metal plates on all sides so as to form a closed box with the ing through one end poses. 1

Preferably, the tube is of a structure such as illustrated and claimed in copending application of Harry M. Gaun-Nathaniel L. Kiser, Serial No. 416,440, filed October 25, 1941, and to which application reference may be made for a detailed description of the tube. However, for the purposes of completing the present disclosure, a typical tube of this construction is illustrated in Figs. 4 and 5 and comprises for example a glass bulb 62 closed off at its lower end by a header 63 which is substantially flattened in a plane transvers to the vertical axis of the tube. Sealed wall for adjustment puradjusting screw 54 extend- 

